A mouth guard is employed for the purpose of preventing a brain concussion and protecting teeth, oral cavity, lips, jaw bones or the like, and it is rather mandatory particularly in contact athletic sports such as American football and boxing. While various materials are used to produce mouth guards, one used largely in these days is an ethylene-vinyl acetate copolymer (hereinafter sometimes abbreviated as EVA). Besides the copolymers, there are mouth guards made of a polyolefinic rubber, silicone rubber, an ethylene-vinyl acetate copolymer supplemented with a thermoplastic polycaprolactone as disclosed in Japanese Patent Gazette No. 2594830. However, since a conventional mouth guard produced from an EVA alone has a low impact absorbability, there has been necessitated to increase its thickness (about 4 mm) in order to increase the impact absorption. Therefore, there are some problems of being not easily conversable, not easily breathing and the like. In addition, the mouth guard has a poor durability, which experiences a tear due to cracks developed during use. Furthermore, the shape of the mouth guard is deformed over a long period, so that the fittability tends to be worsened.
For the reasons described above, there has been proposed in Japanese Patent Laid-Open No. 2001-54610 a mouth guard composition comprising a styrene block copolymer component having excellent durability, an aliphatic saturated hydrocarbon-based resin and/or an ester gum component for giving an impact absorbability and a softening property at a low temperature, and an organopolysiloxane component for reducing stickiness during handling. However, since three or more materials are used as composite relative to a conventional method using an EVA material alone, there are some problems in that processability during the production is worsened, and the equipments become too complicated. In addition, recently, it has been known that a mouse guard clearly has an effect of improving athletic sport performance in addition to the purpose of protecting a brain concussion and protecting teeth, oral cavity, lips, jaw bones or the like. The reasons therefor are considered to be an improved occlusion of the palates and an ability of being able to chew strongly so that a greater power can be exerted. For these purposes, it is important that the mouth guard has an excellent fittability (fitting feel) and is easily chewed upon without causing any vomiting feel due to a feel of a foreign feel (peculiar odor or taste). However, in the above technique, since an organopolysiloxane is contained in an amount of 0.1 to 10% by weight in the composition, there are some problems that the mouth guard has insufficient fittability so that the mouth guard is disengaged easily, or that the mouth guard gives a vomiting feel.